epoll_event(3type) epoll_event(3type) NAME epoll_event, epoll_data, epoll_data_t - epoll event LIBRARY Standard C library (libc) SYNOPSIS #include struct epoll_event { uint32_t events; /* Epoll events */ epoll_data_t data; /* User data variable */ }; union epoll_data { void *ptr; int fd; uint32_t u32; uint64_t u64; }; typedef union epoll_data epoll_data_t; DESCRIPTION The epoll_event structure specifies data that the kernel should save and return when the corresponding file descriptor becomes ready. VERSIONS C library/kernel differences The Linux kernel headers also provide this type, with a slightly different definition: #include struct epoll_event { __poll_t events; __u64 data; }; STANDARDS Linux. SEE ALSO epoll_wait(2), epoll_ctl(2) Linux man-pages 6.7 2023-10-31 epoll_event(3type)